1. Technical Field
This disclosure relates to semiconductor devices, and more particularly, to an apparatus and method for testing the electrical characteristics of a semiconductor chip.
2. Description of the Related Art
After semiconductor chips are packaged, they are typically tested to determine whether defective chips exist. During this process, the electrical characteristics and reliability of the semiconductor chips are evaluated.
Depending on the results of the test, some of the semiconductor chips may be discarded or processed further. It is very important to reliably and precisely test semiconductor chips manufactured through a series of processes to determine whether the semiconductor chips are defective.
FIG. 1 is a sectional diagram illustrating a conventional apparatus 100 for testing a semiconductor chip 50. The scale of the various components of apparatus 100 may be exaggerated for clarity. The apparatus 100 includes a pressurization plate 120 disposed on the semiconductor chip 50, the pressurization plate 120 operable to weigh down the semiconductor chip such that a number of external terminals 55 for the semiconductor chip 50 are connected to a corresponding number of socket pins 110. Accordingly, the apparatus 100 may exchange electrical signals with the semiconductor chip 50 through the socket pins 110.
Socket springs 115 are interposed between the socket pins 110 and a test board 105 such that the socket pins 110 are vertically elastic. In other words, the socket springs 115 are compressed by the weight put on the semiconductor chip 50. Consequently, the external terminals 55 are maintained in physical contact with the socket pins 110.
The physical contact between the socket pins 110 and the external terminals 55 is usually reliable. However, that does not mean that the socket pins 110 always electrically contact the external terminals 55 without fail. Insulating foreign matter may be attached to surfaces of the external terminals 55 and the socket pins 110. Also, the surfaces of the external terminals 55 and the socket pins 110 may be oxidized. These residues may increase contact resistance when the socket pins 110 contact the external terminals 55.
If the apparatus 100 is repeatedly used, the contact resistance between the socket pins 110 and the external terminals 55 becomes very high, thereby causing test errors. In this case, the socket pins 110 must be washed or replaced by new socket pins. As semiconductor chips become faster and operating voltages of the semiconductor chips are lowered, the effects of contact resistance during a test process become increasingly greater.
Embodiments of the invention address these and other disadvantages of the conventional art.